Envelope for winding elements



Feb. 3, 1948.

F. J. SIGMUND ETAL ENVELOPE FOR WINDING ELEMENTS j Filed April 26, 1944 Patented Feb. 3, 1948 ENVELOPE FOR WINDING ELEMENTS Frank J. Sigmund and William s. Hlavin, cleveland, Ohio, assignors to Sigmund Corporation, a corporation of Ohio Application April 26, 1944, Serial No. 532,746

9 Claims. 1

Our invention relates in general to the iluid proofing of winding elements and more particun larly to the fluid-proofing of winding elements for dynamo-electric machines.

An object of our invention is the provision of an envelope for a winding element which is iluidtight.

Another object of our invention is the provision of fluid-prooug the winding elements in the slots of a magnetizable core and still maintain the maximum slot space for the coil windings.

Another object of our invention is the provision of duid-proofing the winding elements in the slots of a magnetizable core and still maintain good heat conductivity between the winding elements and the magnetizable core.

Another object oi our invention is the provision of iluid-proong the winding elements in the slots of a magnetizable core by the employment of split metal sleeves having a slit bridged and sealed by insulating material.

Other objects and a fuller understanding of our invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawing, in which:

Figure 1 represents a side view of a winding element embodying the features of our invention;

Figure 2 is a longitudinal cross-sectional View oi a stator of a dynamo-electric machine to which my invention may be applied;

Figure 3 is an enlarged cross-sectional view of a slot of the winding element and the magnetizable core; and

Figure 4 is a fragmentary and enlarged view of an end of the metal sleeve employed in my invention and being shown extending beyond the end of a slot in the magnetizable core.

With reference to Figure 2 of the drawing, we are illustrating our invention as being applied to the stator of a dynamo-electric machine, although it is to'be understood that our invention applies to the fluid-proofing of winding elements of all kinds. In Figure 2, the stator of the dynamo-electric machine may comprise a magnetic ablecore I which is held together by suitable end rings Il. The magnetizable core is provided with ya plurality of open slots 24 to receive the coil sides I3 of the winding element I2. As illus trated, the Winding element has a top coil head I4 and a bottom coil head I5. Terminal leads Iii extend from the top coil head I4 and are arranged to be connected to a suitable source of supply. The top and bottom coil heads I4 and I5 are re spectively covered with insulating material indiv cated by-the reference characters 25 and 26. The

insulating material 25 and 26 may be applied to the coil heads by dipping the coil heads in a suitable preparation of insulating material or molding or otherwise applying the insulating material thereto to render the coil heads fluid-proof. The winding element shown in Figure 1 is a preformed coil and is arranged to be mounted in the magnetizable core after the coil heads have been properly covered with the insulating material 25 and 26. The coil sides I3 are arranged to be made iluid-proof after they are mounted in the slots 24 of the magnetizable core.

Prior to inserting the coil sides I3 in the slots of the magnetizable core, we provide for mounting a split metal sleeve I'I in each of the coil slots. The split metal sleeves are preferably made of non-magnetizable material and have a relatively thin wall section in order not to occupy too much slot space. As shown in Figure 3, the split metal sleeves I'I may be suitably insulated from the wall of the slots of the magnetizable core by insulating material 21 which may constitute a separate piece of insulation, or it may be bonded to the outside surface of the split metal sleeve I1 and may include vitreous materials.

The inside surface of the split metal sleeve I1 may be provided with a suitable insulating material 28 which may be made of a separate piece of insulation or which may be bonded to the inside surface thereof and may include vitreous materials. The insulating material 21 on the outside of the split metal sleeve I'I may be dispensed with, in which case the split metal sleeves I 1 mechanically engage the wall of the core slots to give good heat conduction.

As shown in Figure 3, the longitudinal edges or lips of the split metal sleeve which constitute a slit to insert the winding therethrough are provided with a longitudinal shoe made of insulating material and bonded thereto. Closely spaced holes IS may be provided along the marginal edge of the sleeve through which the insulating material of the longitudinal shoe may extend in order to mechanically anchor the longitudinal shoe` firmly to the longitudinal edges of the split metal sleeve. The split metal sleeves are longer than the width of the magnetizable core and extend therebeyond and the extended ends 2| are provided with head shoes 23 made of insulating ma terial. Closely spaced holes 22 may be provided around the end of the sleeves 2| in order that the insulating material may extend therethrough and aid in mechanically anchoring the head shoes 23 to the ends of the sleeve. The metal sleeves may y be pre-fabricated with lip and head shoes-made.'

3 of insulating material and bonded thereto or the insulated shoes may be left off during the early stage of the process and later applied When the gap between the lips are closed by the insulating materials. Preferably, the longitudinal shoes 2U and the head shoes 23 are molded to the metal sleeve under pressure whereby a perfect uidtight bond vis established between the metal and the insulating material. The longitudinal edges or lips I 8 and the ends 2l of the metal sleeve may be somewhat roughened or rendered susceptible to receive the insulating material so that the` in,-

sulating material may provide a more perfect bond thereto.

The split metal sleeves I9 either with or without the longitudinal shoes 2li and the head shoe 23 molded thereto, as the case may be, may -be pushed endwise into the core slots 24 preparatory to mounting the coil sides of the winding elementsl in the sleeves.Y In mounting the coil sides I3 in the split metal sleeve, each individual Wire is inserted through the Open-slotsof the core and then througlrthe slit between the longitudinal edges or lips i3 of the metal sleeve. The coil heads extend aroundthe endg of the magnetizable core as shown in Figure 2. The space between the longitudinal shoes 2u is arranged to-be bridged and 'sealed by additional insulating material 29 and the head shoes 23 ion the Aends of the metal sleeves |1`are arranged to be sealed and bonded to the'insulatingmaterial covering -the coil heads by means of additional insulating material S and 3l. In our invention, although dipping or poly.- merizing in situ may be employed, we preferably inject'the insulating material 29, 30 yand 3l into` position by the injecting arrangement shown in Figure 2, which comprises generally a bottom mold 32'suitably connected to the end rings Il' of the magnetizable core and a top mold 33 which engages the-top end ring of the core. An injecting tube 36 extends upwardly throughthezbottom mold 32'and is arranged to have a-plurality oi injecting holes 3l' which register with'the core slots. Positioned above the injecting'tube 36 andtting in the stator core opening is a heater tube 39 which may contain heated liquid or any-otherV heating means for heating the insulatingmaterial as it is injected intothe coil slots. The'bottom mold'i. is providedwith a suitable iiller material into which the coil head lfmay be nested or mounted. As the insulating material is fed through the injecting holesilllfinto the core slots, thematerial flows downwardly andzoutwardly on topoi the ller material 34. The insulating material on top of the ller material 34 is designated by the reference character 35 and isarranged to seal the head shoe 23 on the bottom end'of the metal sleeve to the insulating material 23 which covers'the bottoni coil head i5. As more insulating lmaterial is injected through the injecting holes into thecoil core'slots, the insulatingmaterial rises in the coilsiots until it over.- iows out through an overow duct provided in the top mold 33. The insulating material which flows aroundthe upper end of the magnetizabie core lil provides for'sealingthe shoes E3 on the top end of the split metal Asleeves tothe insulating material 25 which is provided on'the topcoilhead. 'The magnetiza'ble core i0 maybe heatedexternally by a heater case 4i) lled with-a suitable heating iiuid,'whereby the temperature may be maintained at asuitable value Athroughout the stage of injecting the insulating material in-toithemagnetizablecore and'about the winding elements. After i the .insulating material hasset 4 the top and bottom molds, the injecting tube 36 and the heater tube 39 are removed, which leaves the winding elements completely enclosed in an envelope comprising the split sleeves and the insulating material.

By employing split metal sleeves I1 we are able to maintain maximum slot space for the winding elements, while. at the `same time maintaining good heat conduction as well as rendering the winding elements fluid-proof. In our invention since the iiuid cannot flow through the metal sleeves 'the :onlypossible place for iluid to enter the winding elements would be along the bond between thelongitudinal shoes '20 and the longitudinal edgCSof lthemetal sleeve and along the bond between the'head shoes 23 and the end of the sleevesll. Itis noted in the drawing that the insulating longitudinal shoes and the head shoes extend a considerable distance down along the metal, thus providing a large surface area formaking a good bond. Furthermore, the insulating .material is. made heavy or thick in this region which'prevents any fluid Vfrom being transmitted therethrough. Theapplicants flndthat where the*insulatingmaterial is made .relatively thin, the iluid after a prolonged-period of time, is transmitted through the insulating material. in our invention, Vthe-insulating material is made suiciently heavy fto prevent uid'from being* transmitted therethrough, and by using split metal sleeves which have a thin wall section, we are also able tokeep moisture .frompassing into the winding elements since metaldoesnot permit,

the passage. of-uid therethrough.

In :our invention, ythe insulating material Imay be of any suitable type `so;long as vit provides a good fiuidetightbond with the metalsleeve. V'I'he insulating -material should preferably. lhave the qualities of ('1) low water absorption, (2) thigh insulation properties, (3) vgreat'resistance `to chemicals including acids, alkalieaorrosives and gases (4) *.good `:tensile strengthandvi) :easelof application fto themotalliosieevesand readiness of sealing.

Although, Ihave described myinventin .with a.

certaindegree of particulartifl :it is ,understood that -the present disclosurehas :been :made only' by Wav' of example .and what numerous changes in the details'of-oonstruotion and theicombnaf tion and arrangement--of'parts'maybe reSQrtedto without departingfrom thespiritand thescope sleeve .extending betweenthe Viirstand-secondmassesoi insulating :matel'iL and all?ildiii'ill-l1` mass rof insulating material bridging thesaid slit and sealing.theiends-ofzthexnetalgSleeveergopeer tively with; the Yf-iirst and secondmesses of insulating materi-al.

2. In an electricalgdevicehaving a magnetiaable core with: open, slots and winding elementsinlsaid slots, the; improvement enclosure; means for portion of the'windinarelemen-ts in'soid5sloieseid improvement comprising o spiitrmetel fsleoveor :having insertion in each slot and extending at least the length -of said slots, each of said sleeves having a slit to receive the winding elements, and a mass of insulating material bridging and sealing the slits of the said sleeves.

3. In an electrical device having a magnetizable core with open slots and winding elements having coil sides in the slots and coil heads extending around the ends of the core, the improvement of an envelope for the winding elements, said envelope comprising a rst and second mass of insulating material covering respectively the coil heads, and closure means in each-of the slots for the coil sides, each of said closure means including a split metal sleeve having a slit to receive the coil sides, saidgsleeves extending between the ilrst and second masses of insulating material, and an additional mass of insulating material bridging the said slits and sealing the ends of the metal sleeve respectively with the first and second masses of insulating material.

4. In an electrical device having a magnetizable core with open slots and winding elements having coil sides in the slots and coil heads extending around the ends of the core, the process for providing an envelope around the winding elements comprising the steps of providing ilrst and second masses of insulating material respectively around the coil heads, providing a split metal sleeve with a slit for each of the slots and inserting the sleeves in said slots with the slits registering with the open slots, inserting the coil sides into the split sleeves through the open slots and the registering slits, and applying insulating material into the slits of the metal sleeves and between the ends of the metal sleeves and the ilrst and second masses of insulating material. respectively.

5. In an envelope for a winding element, the improvement of closure means for a portion of the winding element, said improvement comprising a split tubular metal sleeve having a slit to receive said portion of the winding element, and a mass of insulating material bridging and sealing the said slit, said metal sleeve having its inside surface coated with an insulating vitreous material.

head portions at the ends of the core, closure means for the side portion comprising a split metal sleeve enveloping said coil side in the slot and extending at least the full length of the slot 'and having a cross-sectional outline substantially conforming to the general contour of the side wall of the slot, and a'mass of insulating material bridging and sealing the slit of the sleeve and extending to the coil heads and .enveloping and sealing said heads.

7. In a magnetizable laminated core having at least an open slot therein and a winding element in said slot, the provision of a split metal sleeve extending at least the length of the slot and having a cross-sectional outline substantially conforming to the general contour of the side wall of the slot.

8. In a magnetizable laminated core having at least an open slot therein and a winding element in said slot, the provision oi' a split metal sleeve extending at least the length of the slot and having a cross-sectional outline substantially conforming to the general contour of the side wall of the slot, said metal sleeve having an electrical insulating coating on at least one side thereof.

9. In a. magnetizable laminated core having at least an open slot therein and a winding element in said slot, the provision of a. split metal sleeve extending at least the length of the slot and having a cross-,sectional outline substantially conforming to the general contour of the side wall of the slot, said metal sleeves being insulated from said windings by a layer of insulating material positioned therebetween.

FRANK J. SIGMUND. WILLIAM S. HLAVIN.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,387,389 Haverli et al. Aug, 9, 1921 1,732,607 Dominguez Aug. 6, 1929 403,2.62 Garland May 14. 1889 FOREIGN PATENTS Number Country Date 25,834 Great Britain 1907 559,649 Germany June 1, 1934 

